Core-Shell Structured Bi/BiOBr Photoelectrodes for Efficient Photoelectrochemical Water Splitting

Two-dimensional ternary compounds bismuth oxyhalides (BiOxBry) with suitable band gap and high surface bulk ratio have great potentials for photoelectrochemical water splitting. Although intensive efforts were devoted to the design of well-defined nanostructures to optimize the photoreactivity, it remains a great challenge to improve the light absorption capacity and charge carrier transfer of the materials. In this work, we developed a controllable synthesis route to prepare core-shell structured Bi/BiOBr complexes with abundant conduction channels and active edges as photoelectrodes. The structure and morphology of the Bi/BiOBr complexes could be modulated by tuning the thickness of Bi thin film and/or the oxygen gas flow during the annealing process. Photoelectrochemical analyses indicated that the photocurrent density of the Bi/BiOBr electrodes reached up to 0.36 mA cm(-2). at -0.4 V versus reversible hydrogen electrode (RHE) in acid environments, which was 1 order large than that based on pure BiOBr thin film electrodes (0.08 mA cm(-2)). Our study demonstrates that the controllable synthesis of Bi/BiOBr core-shell structures may open a new way for engineering 2D layered ternary compounds materials to develop novel catalyst devices.